Cannot connect to TV via HDMI

ArmedReader · 2022-11-17 06:04:05

Hello,

I am trying to connect my Samsung TV as an external display to my computer via an NVIDIA 2070. I currently have all the NVIDIA drivers installed and configured correctly (I believe). I am using X11 with KDE.

When I plug the my directional HDMI cable into the GPU, most of the time nothing shows up in the KDE display settings window. On a *rare* occasion, I do see a very generic configuration called "HDMI-0" pop up in the KDE display settings window when I plug the HDMI cable in.

I know my cable is OK because when I plug the HDMI cable into my laptop (also running Arch with X11 but with Intel open source drivers), it works flawlessly every time.

I'm not really sure how to debug this. Here's my xrander output with my main display (working -- DP-2) and HDMI cable (not working -- HDMI-0) connected.

```
00:02:22 ~ $ xrandr
Screen 0: minimum 8 x 8, current 1920 x 1080, maximum 32767 x 32767
DP-0 disconnected (normal left inverted right x axis y axis)
DP-1 disconnected (normal left inverted right x axis y axis)
HDMI-0 disconnected (normal left inverted right x axis y axis)
DP-2 connected primary 1920x1080+0+0 (normal left inverted right x axis y axis) 531mm x 299mm
1920x1080 119.98 + 143.85* 119.88 100.00 99.90 60.00 59.94 50.00 29.97 25.00 23.98
1680x1050 59.95
1600x1200 60.00
1440x900 59.89
1400x1050 59.98
1280x1024 75.02 60.02
1280x960 60.00
1280x720 60.00 59.94 50.00
1024x768 75.03 70.07 60.00
800x600 75.00 72.19 60.32 56.25
720x576 50.00
720x480 59.94
640x480 75.00 72.81 59.94 59.93
DP-3 disconnected (normal left inverted right x axis y axis)
DP-4 disconnected (normal left inverted right x axis y axis)
DP-5 disconnected (normal left inverted right x axis y axis)
USB-C-0 disconnected (normal left inverted right x axis y axis)
```

Any help is appreciated. Thank you.

d.ALT · 2022-11-17 07:42:23

ArmedReader wrote:

directional HDMI cable

Do you mean a cable with one end HDMI (male) and the other DisplyPort (male)? Bear in mind such cables don't always work as guarantee! You'd buy high quality cables, or - better - active DiplayPort--->HDMI adapters!

- Did you enable Input Signal Plus on your source's TV?
- Let's try common FULL-HD standard resolution (kwnown-to-be-working):

$ xrandr --output DP-2 --mode 1920x1080 --rate 60

seth · 2022-11-17 08:54:06

high quality cables

is not a thing w/ HDMI, but yes

most of the time nothing shows up in the KDE display settings window. On a *rare* occasion

means that it is very most likely the cable, in doubt the plugs and

when I plug the HDMI cable into my laptop (also running Arch with X11 but with Intel open source drivers), it works flawlessly every time

is meaningless because HDCP is designed to be a race condition.
Does it matter whether you connect the cable to the running system or before booting?

On a formal note, fluxBB predates and doesn't use nor support markown, https://bbs.archlinux.org/help.php#bbcode

ArmedReader · 2022-11-17 14:30:15

d.ALT wrote:

Do you mean a cable with one end HDMI (male) and the other DisplyPort (male)?

No, the HDMI cable is male on both sides, but there is a source and an output side to the cable.

seth wrote:

is meaningless because HDCP is designed to be a race condition.

Can you expound what you mean by this? I'm not quite sure I get your meaning.

seth wrote:

Does it matter whether you connect the cable to the running system or before booting?

No it does not matter. It doesn't work with the NVIDIA GPU either way.

For what it's worth, here's the HDMI cable I'm using.

ArmedReader · 2022-11-17 14:37:13

Oh! Just this morning, after doing nothing and waking my computer from sleep, I see my TV appearing as a valid device.

Here's my output of xrandr now:

08:31:53 ~ $ xrandr
Screen 0: minimum 8 x 8, current 1920 x 1080, maximum 32767 x 32767
DP-0 disconnected (normal left inverted right x axis y axis)
DP-1 disconnected (normal left inverted right x axis y axis)
HDMI-0 connected (normal left inverted right x axis y axis)
   1024x768      60.00 +
   1600x900      59.82  
   1400x900      59.88  
   1368x768      59.88    59.85  
   1280x800      59.91    59.81  
   1280x720      59.86    59.74  
   1024x576      59.90    59.82  
   960x540       59.82    59.63  
   864x486       59.92    59.57  
   800x600       72.19    60.32    56.25  
   800x450       59.82  
   700x450       59.88  
   684x384       59.88    59.85  
   640x480       59.94  
   640x400       59.98    59.88  
   640x360       59.86    59.83  
   512x384       60.00  
   512x288       60.00    59.92  
   480x270       59.82    59.63  
   432x243       59.92    59.57  
   400x300       72.19    60.32    56.34  
   320x240       60.05  
DP-2 connected primary 1920x1080+0+0 (normal left inverted right x axis y axis) 531mm x 299mm
   1920x1080    119.98 + 143.85*  119.88   100.00    99.90    60.00    59.94    50.00    29.97    25.00    23.98  
   1680x1050     59.95  
   1600x1200     60.00  
   1440x900      59.89  
   1400x1050     59.98  
   1280x1024     75.02    60.02  
   1280x960      60.00  
   1280x720      60.00    59.94    50.00  
   1024x768      75.03    70.07    60.00  
   800x600       75.00    72.19    60.32    56.25  
   720x576       50.00  
   720x480       59.94  
   640x480       75.00    72.81    59.94    59.93  
DP-3 disconnected (normal left inverted right x axis y axis)
DP-4 disconnected (normal left inverted right x axis y axis)
DP-5 disconnected (normal left inverted right x axis y axis)
USB-C-0 disconnected (normal left inverted right x axis y axis)

This intermittent behavior is very weird. It's also still not giving me proper resolutions for the TV. There should be much higher resolution options for my HDMI-0 output.

d.ALT · 2022-11-17 14:37:41

ArmedReader wrote:

For what it's worth, here's the HDMI cable I'm using.

So I wonder why xrandr "sees" the connection on DisplayPort (DP-2)... Are you attached to two displays? DP-2 = PC monitor and HDMI-0 = Samsung TV?

Also, as seth good pointed out: try plugging-in the Samsung TV's HDMI before booting up you computer.

d.ALT · 2022-11-17 14:39:15

ArmedReader wrote:

It's also still not giving me proper resolutions for the TV. There should be much higher resolution options for my HDMI-0 output.

https://www.samsung.com/us/support/answer/ANS00082465/

seth · 2022-11-17 14:39:32

He's got two outputs all along, no problem on DP2, but HDMI is wonky.
The reason is usually this PoS: https://en.wikipedia.org/wiki/High-band … Protection

Edit:

There should be much higher resolution options for my HDMI-0 output.

Make sure you've https://wiki.archlinux.org/title/NVIDIA … de_setting enabled and then check

edid-decode < /sys/class/drm/card0-HDMI-0/edid

https://aur.archlinux.org/packages/edid-decode-git

Also your xorg log, https://wiki.archlinux.org/title/Xorg#General to see whether nvidia filters resolutions.
You can in doubt https://wiki.archlinux.org/title/Xrandr … esolutions but that will require you to pass "AllowNonEdidModes" to "ModeValidation" eg. /etc/X11/xorg.conf.d/20-nvidia.conf

Section "Device"
    Identifier     "Device0"
    Driver         "nvidia"
    Option         "ModeValidation" "AllowNonEdidModes, NoHorizSyncCheck"
EndSection

Last edited by seth (2022-11-17 14:45:48)

ArmedReader · 2022-11-17 14:39:38

d.ALT wrote:

Are you attached to two displays? DP-2 = PC monitor and HDMI-0 = Samsung TV?

Yes, that's exactly right.

d.ALT · 2022-11-17 14:43:06

seth wrote:

The reason is usually this PoS: https://en.wikipedia.org/wiki/High-band … Protection

Never ever had any problems with HDCP (PCs, laptops, nVIDIA GPUs, TVs...) in my entire life! So can I consider myself lucky?

ArmedReader · 2022-11-17 14:44:38

I understand now Seth, thank you. Do you have any recommendations on how to get around HDCP? I would like to have a high resolution picture on my TV. Would a display port to HDMI converter do the trick?

d.ALT · 2022-11-17 14:45:56

ArmedReader wrote:

Would a display port to HDMI converter do the trick?

Types of connections include DisplayPort (DP), Digital Visual Interface (DVI), and High-Definition Multimedia Interface (HDMI),
(https://en.wikipedia.org/wiki/High-band … Protection)

seth · 2022-11-17 14:50:58

The whole point of hdcp (which fails on weak signals, because the design is a race condition w/o any margin for error - if you need to resend data, the handshake will fail) is to not be circumvented.
The handshake fails, and your Tv says good bye.

The only way to deal w/ this is a better™ cable, which is chinese roulette, but the higher the grade and the shorter the cable, the better the chances you get through.
This is a german article, but it has a nice matrix - and the marketing bullshit on the leftmost column is actually the official version/feature indicator:
https://de.wikipedia.org/wiki/High_Defi … enschaften

Would a display port to HDMI converter do the trick?

Adding another point of failure will rather not help (unless the issue is w/ the jack on the GPU rather than the cable… but it's usually the cable)

Edit: the difference w/ DP is that hdcp wasn't tacked on in the last minute - the handshake is typically more reliable.

Last edited by seth (2022-11-17 14:52:10)

d.ALT · 2022-11-17 14:59:45

ArmedReader wrote:

For what it's worth, here's the HDMI cable I'm using.

50feet = 15mt is a bit too long!
As seth suggested: signal cables (audio, video, etc...) ---> the shorter the better

ArmedReader · 2022-11-17 15:19:29

It's a bummer to hear that it's likely the cable because I did not buy a cheap cable from Amazon. According to the table (matrix) you linked, Seth the speeds for my cable should be in the "HDMI ultra high speed" category with a data rate of 48 Gbps which matches what the Amazon cable listing says.

I know 50 feet (15M) is a bit long for a cable, but they make a 100 foot (30M) version of this cable too.

Also, I'm still not able to figure out why it works OK on my laptop and why it doesn't on my GPU. This still seems strange to me.

seth · 2022-11-17 15:36:57

Signal strength/quality of the output, tension on the plug, … if it wasn't also on the boot, I'd consider sideload, causing the system be too slow on the handshake.
If you can, try a short cable.

Arch Linux

#1 2022-11-17 06:04:05

Cannot connect to TV via HDMI

#2 2022-11-17 07:42:23

Re: Cannot connect to TV via HDMI

#3 2022-11-17 08:54:06

Re: Cannot connect to TV via HDMI

#4 2022-11-17 14:30:15

Re: Cannot connect to TV via HDMI

#5 2022-11-17 14:37:13

Re: Cannot connect to TV via HDMI

#6 2022-11-17 14:37:41

Re: Cannot connect to TV via HDMI

#7 2022-11-17 14:39:15

Re: Cannot connect to TV via HDMI

#8 2022-11-17 14:39:32

Re: Cannot connect to TV via HDMI

#9 2022-11-17 14:39:38

Re: Cannot connect to TV via HDMI

#10 2022-11-17 14:43:06

Re: Cannot connect to TV via HDMI

#11 2022-11-17 14:44:38

Re: Cannot connect to TV via HDMI

#12 2022-11-17 14:45:56

Re: Cannot connect to TV via HDMI

#13 2022-11-17 14:50:58

Re: Cannot connect to TV via HDMI

#14 2022-11-17 14:59:45

Re: Cannot connect to TV via HDMI

#15 2022-11-17 15:19:29

Re: Cannot connect to TV via HDMI

#16 2022-11-17 15:36:57

Re: Cannot connect to TV via HDMI

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